Radioisotopes and the Age of the Earth

Abstract

RATE is an acronym applied to a research project investigating radioisotope dating sponsored by the Institute for Creation Research and the Creation Research Society. It stands for Radioisotopes and the Age of The Earth. This article summarizes the purpose, history, and intermediate findings of the RATE project five years into an eight-year effort. It reports on the latest status of the research on helium diffusion through minerals in granitic rock, accelerated nuclear decay theory, radiohalos, isochron discordance studies, case studies in rock dating, and carbon-14 in deep geologic strata. Each of the RATE scientists will present separate technical papers at the Fifth International Conference on Creationism on the details of this research.

This paper was originally published in the Proceedings of the Fifth International Conference on Creationism, pp. 337–348 (2003) and is reproduced here with the permission of the Creation Science Fellowship of Pittsburgh (www.csfpittsburgh. org).

Introduction

The conventional scientific view typically expressed
today is that the earth is about 4.6 billion years old and the universe between
10 and 20 billion years old. These estimates are based primarily on the abundances
of parent and daughter radioisotopes and the implications of stellar and
cosmological models. Yet, a literal interpretation of Scripture and much
scientific evidence has been gathered to indicate that the creation of the
earth, the solar system, and the universe occurred only a few thousand years
ago.

One of the principal forces which has traditionally
driven estimates of an old age for the earth is the necessity for long periods
of time for evolution. Even before radioactivity was discovered in the 1890s,
estimates of the age of the earth were growing longer and longer as the complex
nature of life became more evident. However, it has never been demonstrated
that the evolution of life from inorganic chemicals has occurred or that life
has evolved from simple life forms to the complex ones we see today. Living
systems, even the simplest ones, are based upon symbolic language structures of
extreme complexity. There is no hint in the laws of chemistry and physics that
matter on its own can ever generate symbolic language regardless of the time
allowed. Because it has no solution to this fundamental difficulty,
evolutionary dogma is now facing a major crisis that long periods of time
simply cannot mend.

Young-earth creationists on the other hand are not
convinced that long periods of time have transpired since the origin of the
earth—and some include the origin of the entire universe. In defending a
young-earth position, they typically point to important assumptions underlying
these dating schemes. For example, when a parent isotope decays into a daughter
isotope, the initial concentration of the daughter isotope may affect the
estimate of time since the process started. Creationists in some cases question
the conventional assumption that the initial amount of daughter product is
small or at least can be tightly constrained. Isochron methods attempt to
remove this uncertainty, but the results are not wholly satisfactory. Also
often questioned by creationists are the assumptions that the quantities of the
parent and daughter isotopes have not been altered by non-radioactive processes
such as migration and transport, and that the rate of decay from parent to
daughter has been constant during the period under consideration. Most
researchers attempt to justify each of these three assumptions, but ultimately
no one can be certain if the conditions have been met, particularly over long
periods of time.

It is hypothesized by the RATE group that at some time
in the past much higher rates of radioisotope decay have occurred, leading to
the production of large quantities of daughter products in a short period of
time. It has been suggested that these increased decay rates may have been
associated with the rock-forming processes on the early earth, and possibly one
of the results of God’s judgment upon man following creation. The RATE group
suspects that large amounts of radioactive decay may have occurred during the
first two and a half days of creation as part of the supernatural creation
process. The jury is still out and, until we complete our research phase, this
thesis remains tentative. The presence of supernatural “process” during
creation is essential to our approach, however. Scripture talks of at least two
major events which occurred after creation, the Judgment in the Garden of Eden
and the Flood. It would seem appropriate to consider at least that an original
distribution of elements could have been mixed, and radioactive processes
speeded up during one or both of these events.

History of the RATE Project

On July 5, 1997 a group of young-earth creationist
researchers met in San Diego, California to address the issue of reconciling
radioisotopes and the age of the earth as reported by Vardiman.1 It
was recognized by the group that this was a significant problem which must be
addressed if young-earth creationism was to continue to have a significant
impact on the issue of origins both within and outside the Christian community.
The group, which has since become known as RATE, decided that the primary
approach would be to explore accelerated rates of decay of radioisotopes during
one or more of the Creation, Fall, and Flood events. A second approach would be
to address the mixing of mantle and crustal reservoirs since the origin of the
earth. Additional processes and issues have been suggested and explored as part
of the research. The focus of the RATE research would be primarily on long-age
isotopes and their use as chronometers.

By February, 2003 six annual meetings of RATE had been
held by the principal investigators. These meetings included reports,
discussion, allocation of funds, and research decisions. During the third
meeting thirteen research experiments were identified as shown in Tables 1 and
2. A brief description of each experiment, expected results, the estimated
cost, and estimated time were developed. At the annual meeting in 2001 the
importance to this project of 14C in deeply buried fossil material
was identified, and a research thrust on this topic was added. The cost of the
eight-year project was estimated to be about $500,000. Before 2002 about 80% of
these funds had been raised through private donations. Two major reports were
planned for RATE. The first report, a 675-page book was published in December
2000 entitled, Radioisotopes
and the Age of the Earth: A Young-Earth Creationist Research Initiative. It contains an introduction to the project, a report
on the literature searches by the principal investigators on most of the topics
of concern, a glossary, and a set of research proposals. The purpose of the
initial report was to stake a claim. It was also published to lend structure
and direction to the effort and to inform contributors about what they could
expect from their donations. The second and final book is planned to be
published in 2005 and is expected to be titled Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Report. It will
report on the findings of the five-year research phase.

Intermediate Results of RATE Research

Helium Diffusion—Dr. D. Russell Humphreys, PI

Two decades ago, it was reported by Gentry, Glish, and
McBay2 that up to 58% of the helium (a daughter product of uranium
and thorium decay) generated during the alleged 1.5 billion year age of the
Precambrian granodiorite beneath the Jemez Mountains near Los Alamos, New
Mexico, was still in the zircons embedded in the biotite crystals contained
within the granodiorite. Yet, the zircons were so small (see Fig. 1 for a
picture of typical zircons) that they should not have retained the helium for
even a small fraction of that time. The high retentions suggest to us and many
other creationists that the helium has not had time to diffuse out of the
zircons—that accelerated nuclear decay produced over a billion years worth of
helium only thousands of years ago. Such accelerated decay could reduce the
radiometric timescale from gigayears down to months.

A theoretical creationist model, based on observed
helium retention, of diffusion rates of helium over a period of 6,000 years was
reported by Humphreys3 and Humphreys et al.4). It
compares well with laboratory measurements in Jemez zircons, as shown in Fig.
2. The solid dots show the diffusion coefficient as a function of inverse
temperature for the measurements with the Jemez zircons and the solid lines
through empty squares show the theoretical predictions from the theoretical
model. There is a five-order-of-magnitude difference (100,000 ×) between the predictions of diffusion for
the evolutionist and creationist models. The measured diffusion rates of He
predict that helium would leak out of a zircon/biotite matrix in a period of
time on the order of thousands of years, not hundreds of millions of years.
This is consistent with the high concentrations of helium still found in the
Jemez granodiorite.

Table 1. High priority RATE experiments.

Experiment

Description

Expected Results

Time

He
Diffusion

Determine He
diffusion rates through minerals under various conditions

Acquisition of data
on which to base a claim that the amount of He in rocks today should not be
so high if it was produced by nuclear decay over millions of years. If the He
was produced within the most recent thousands of years, it would be expected
to remain still in the rocks as observed.

2 years

Isochron
Discordance

Construct 5-point
mineral and whole-rock isochrons on selected basaltic rocks formed during the
Flood

Increased evidence
for discordance among isotopic dating methods using isochrons for mineral
components of Flood-related rocks. Based on the consistency of the
discordance from these specimens and others, infer the processes which led to
the distribution of isotopes.

2 years

Nuclear
Decay Theory

Conduct a literature
search for evidence and models of accelerated nuclear decay and adapt to a
creationist worldview, if appropriate. Complete studies on a and b decay.

Increase evidence
that nuclear decay can vary radically in response to changes in cosmological
“constants” and environmental effects. Associate other likely effects with
biblical statements and observational data.

2 years

Radiohalos

Determine the
geological distribution of Po halos, their proximity to concentrations of U
and the relationship to different halo types.

Resolve the question
if Po halos are special evidence for created rocks only , or could they also
occur in Flood rocks. This effort may also allow inferences about the process
of radioisotope decay and halo formation.

5 years

Fission
Tracks

Estimate nuclear
decay rates during the Flood using the fission track method. Select an
initial sample from a tuff bed in the Muav Formation of Grand Canyon.

Fission track
estimates of nuclear decay rates are thought to be absolute following rock
formation and do not inherit prior evidence of decay. It is important to know
if decay rates were accelerated during the Flood.

2 years

Additional laboratory measurements and modeling studies
of helium diffusion in zircon are expected to lead to a further refinement of
the creationist model. The data of Fig. 2 indicate an age between 4,000 and 14,000
years since the helium began to diffuse from the zircons. This is far short of
the 1.5 billion year evolutionist age! We believe that the final results will
resoundingly support our hypothesis concerning diffusion and radiogenic helium.

Nuclear Decay Theory—Dr. Eugene F. Chaffin, PI

The quantum theory of alpha and beta decay are being
reviewed by Chaffin,5,6 with extensions of the standard models being
explored to see if they could lead to accelerated decay during episodic
variations of the coupling constants. Variations in the radii of compactified
extra dimensions and consequent variation in coupling constants over the
history of the universe could cause accelerated decay. If, during early
Creation Week, say the first 2+ days before the creation of plants, such
variations were to occur, they could lead to accelerated nuclear decay, thus
adjusting isotopic abundances, without giving unacceptable doses of radiation
to life. Part way through day 3, God created grasses, herbs, and fruit trees
which could have been damaged by high radiation. Or, during the Fall of Genesis
3, or during the Genesis Flood, smaller variations are possible.

Fig. 2. Plot of diffusion coefficient of He in zircon vs. inverse temperature.

Fig. 3. Plot of nuclear potential energy vs. radial distance from the center of a nucleus.

These variations may help explain the abundances of
radioisotopes, including radioactive equilibrium found in decay chains such as
the uranium series, within the young-earth time frame. We are also exploring
the tunneling theory of alpha decay to see how much change in half-life is
possible without drastically affecting other measurable properties of nuclei.
For only slight changes in the depth of the nuclear potential well
(see Fig. 3), abrupt changes in the number of nodes of the alpha particle wave
function occur which can lead to drastic changes in half-life. Also, the
half-life depends exponentially on the shape of the potential well, so that
even slight changes are effective in accelerating alpha-decay.

Radiohalos—Dr. Andrew A. Snelling, PI

The significance of radiohalos is due to the fact they
represent a physical, integral historical record of the decay of radioisotopes
in the radiocenters over a period of time as discussed by Snelling7
and Snelling and Armitage.8 The darkening of the minerals
surrounding the radiocenters is caused by damage to their crystal structure by
alpha particles produced by nuclear decay. As part of a systematic effort to
investigate radiohalo occurrences in granitic rocks globally and throughout the
geologic record, suitable samples have been collected from the La Posta
(southern California), Stone Mountain (near Atlanta, Georgia) and Cooma
(southern New South Wales, Australia) plutons.

Fig. 4. Number of radiohalos vs. type and location.

The biotite crystals in all these granites contain
abundant 238U, 210Po, and 214Po radiohalos.
The occurrence ratio is approximately five 210Po radiohalos for
every 214Po and 238U radiohalo, which occur roughly in
equal numbers except in the Cooma pluton (see Fig. 4). While these radiohalos
are homogeneously distributed throughout the mineralogically uniform Stone
Mountain pluton, they are almost exclusively concentrated in the
muscovite-biotite granodiorite core of the La Posta pluton. Furthermore, there
are four to five times more of all these radiohalos in the associated
late-stage, Indian Hills granite (southern California).

Hydrothermal fluids are invariably concentrated in the
last liquid phases during the rapid convective cooling of granite plutons as
discussed by Snelling and Woodmorappe,9 so this pattern of radiohalo
occurrence in the La Posta pluton and Indian Hills granite strongly suggests
that the Po radiohalos have formed as a result of late hydrothermal fluid
transport of Po radioisotopes locally within the biotite flakes separating them
from their parent 238U in the zircons.The Cooma granite was produced
by partial melting at the center of a regional metamorphic complex. Thus, this
research has the potential to demonstrate that both the cooling of granite
plutons and regional metamorphism occurred within weeks to months, not over
millions of years, because of the short half-life of 218Po.
Radiohalo occurrences in other granitic plutons at many levels in the geologic
record are also under continuing investigation.

Isochron Discordance—Dr. Steven A. Austin, PI

Field observations, petrographic study, and geochemical
analysis by Snelling, Austin, and Hoesch10 indicate that a
95-meter-thick sill in sharp contact with the intruded Hakatai shale near Bass
Rapids in Grand Canyon was well mixed isotopically when emplaced. However,
after intrusion, it segregated mineralogically and chemically by crystal
settling. Such a condition of thorough isotopic mixing followed by rapid
chemical segregation is ideally suited to test the assumptions that underlie
whole-rock and mineral isochron dating. Both creationists and evolutionists
should accept the well-mixed initial isotopic condition of the original magma
body.

Fig. 5. Isochron age vs. half-life and mode of decay.

New K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb radioisotope data from
eleven whole-rock samples (eight diabase, three granophyre) and six mineral
phases separated from one of the whole-rock diabase samples yield discordant
whole-rock and mineral isochron “ages.” These isochron “ages” range from 842 ± 164 Ma (whole-rock K-Ar) to 1375 ± 170 Ma
(mineral Sm-Nd). (See Fig. 5 for a graph of the isochron “age” versus half-life
and type of decay for each of the four radioisotope systems investigated.)
Although significant discordance exists between the K-Ar, Rb-Sr, Sm-Nd, and
Pb-Pb radioisotope methods, each method appears to yield concordant “ages”
internally between whole rocks and minerals. Internal concordance is best
illustrated by the Rb-Sr whole-rock and mineral isochron “ages” of 1055 ± 46 Ma and 1059 ± 48 Ma, respectively. It is, therefore, argued
that only changing radioisotope decay rates in the past could account for these
discordant isochron “ages” for the same geologic event. Furthermore, these data
are consistent with alpha decay having been accelerated more than beta decay,
and with a greater acceleration factor for a greater present half-life.

Case Studies in Rock Dating—Dr. Andrew A. Snelling, PI

Snelling11,12 earlier reported having
obtained K-Ar model ages for recent andesites collected from Mt. Ngauruhoe in
New Zealand. Dates of less than 0.27 to 3.5 Ma could not be reproduced, even from splits of the same
samples from the same flow, the explanation being variations in the 40Ar*
(radiogenic 40Ar) content in excess of the “zero-age” amount. It was
concluded that this excess 40Ar* had been inherited by these magmas
during their genesis in the upper mantle.

Two samples from each of the lava flows and deposits
have now been analyzed for Rb-Sr, Sm-Nd, and Pb-Pb isotopes. Together with the
trace and rare earth element analyses, they further elucidate the petrogenetic
history of these andesites, including crustal components which may have
contaminated originally pure basalt magmas. Whereas valid isochron ages cannot
be obtained from this isotopic data except by subjective manipulation, depleted
mantle Nd model ages of 801–1594 Ma and positive εNd(to) values suggest the original basalt magmas
were generated from partial melting of the residual solids in old depleted
upper mantle, while the large positive εSr(to) values and the 87Sr/86Sr
ratios suggest contamination during their ascent with basement greywackes to
produce the andesite magmas. Consequently, evidence continues to accumulate
that systematic mixing of mantle and crustal sources makes it nearly impossible
to obtain unambiguous radioisotopic results in these environments.

Fig. 6. Petrogenetic model of melt formation near a subducting slab, based on Tatsumi17 and Davies and Stevenson.18 Mixing and inheritance of radioisotopes invalidate conventional age dating.

The petrogenetic model therefore favored by Gamble et
al.,13 which is consistent with all the isotopic data discussed in
Snelling,14 and shown in Fig. 6, is based on Tatsumi15
and Davies and Stevenson.16 This model envisages a zone of melt
formation approximately coincident to the volcanic front, which includes
Ruapehu and Ngauruhoe, and a melt generation region delimited by the interface
of the subducting slab, the base of the arc lithosphere (of continental New
Zealand) and two vertical columns, one delineating the volcanic front, the
other, the coupled back-arc basin. Fluids liberated from the descending slab
ascend into and enrich the overlying periodite down to higher pressures, where
the amphibole breaks down giving rise to amphibole dehydration, while
progressive dehydration reactions in the slab itself lead to fluid transfer
from the slab into the mantle wedge, both processes producing partial melting
as amphibole breaks down over the depth range 112 ± 19 km as
discussed by Tatsumi19 and Davies and Stevenson.20 The
lower density melt then rises and pools in the upwelling melt column,
eventually penetrating upwards into the overlying arc lithosphere to fill magma
chambers that then erupt when full.

The Rb-Sr, Sm-Nd, and Pb-Pb radioisotopic ratios in the
samples of this study of recent (1949–1975) andesite lava flows at Mt.
Ngauruhoe, New Zealand, as anticipated, do not yield any meaningful age
information, even by selective manipulation of the data. Instead, these data
provide evidence of the mantle source, of magma genesis, and of the crustal
contamination of the parental basalt magmas. By implication, the radioisotopic
ratios in ancient lavas found throughout the geologic record must similarly
express the fundamental characteristics of their geochemistry. They therefore
must also strongly reflect the magmatic origin of the lavas from mantle and
crustal sources and any history of mixing or contamination in their
petrogenesis which can dramatically distort any inferred isotopic age. Even
though radioisotopic decay has undoubtedly occurred during the earth’s history,
conventional radioisotopic dating of these rocks therefore cannot provide valid
absolute ages for them. This is especially so if accelerated nuclear decay
accompanied the catastrophic geologic and tectonic processes responsible for
the mixing of the radioisotopic decay products during magma genesis.

Fifteen rock samples have also been collected from the
Somerset Dam gabbro intrusion near Brisbane, Australia (Snelling21),
probably a well-preserved, unmetamorphosed subvolcanic magma chamber. The
samples were processed and submitted to various laboratories for whole-rock
major and trace element analyses and for K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb
radioisotopic analyses. Additionally, one of the gabbro samples from one of the
cyclic units was separated into its mineral constituents using heavy liquids,
and the resultant plagioclase, augite, olivine, and magnetite-ilmenite
concentrates, along with a duplicate piece of the whole-rock, submitted for
K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb radioisotopic analyses.

The objective of this study was not only to compare the
different dating methods, but also to compare whole-rock and mineral isochron
ages and to test whether there are variations in the radioisotopes between the
cyclic units, and between the macrolayers within them. From these studies it
may be possible to infer how mixing occurs in a magma chamber and demonstrate
that radioisotopic compositions of crustal rock may reflect characteristics of
the magma sources in the mantle rather than the ages of the intrusion.

Significant Amounts of 14C in Deep Strata—Dr. John R. Baumgardner, PI

Fig. 7. Distribution of 14C values for biogenic samples from the radiocarbon literature. Given their position in the geological record, all these samples should contain no detectable 14C according to the conventional geological timescale.

According to the conventional geologic time-scale,
organic materials older than about 250,000 years should be utterly 14C
“dead.” This is because the half-life of 14C, only 5,730 years, is
so short. 250,000 years of decay (corresponding to 43.6 half-lives) reduces the
number of initial 14C atoms by a factor of 7 × 10-14. A gram of modern carbon contains about 6 × 101014C atoms, so not a single 14C
atom should remain after 250,000 years. The astonishing result, however, is
that, almost without exception, when tested by accelerator mass spectrometer
(AMS) methods, organic samples from every portion of the Phanerozoic record
show detectable and reproducible amounts of 14C! This reality has
been established as dozens of AMS laboratories around the world over the last
20 years have sought desperately to understand why organic samples from deep
within the geological record, thought to be tens to hundreds of millions of
years old, should consistently contain 0.1–0.5% of the modern level of 14C.
Believing this 14C had to be contamination, they have mounted an
intense quest to identify and eliminate sources of contamination in their AMS
procedures. But despite improvements in techniques, this level of 14C,
on the order of 0.1–0.5 percent modern carbon (pmc), continues to be reported
for samples that, given their location in the geological record, should be
entirely 14C “dead.” Many scores of such measurements are readily
available in the standard peer-reviewed radiocarbon literature as documented by
Giem22 and Baumgardner et al.23 and displayed in Fig. 7.
Measurable 14C at roughly uniform values in pre-Flood organic
materials fossilized in Flood strata, of course, represents powerful support
for the young earth Creation-Flood model.

Aware of this, Snelling24,25,26,27,28 analyzed the 14C
content of fossilized wood conventionally regarded as 14C “dead”
because it was derived from Tertiary, Mesozoic, and upper Paleozoic strata
having conventional ages of 40 to 250 million years. All samples were analyzed
using AMS technology by a reputable commercial laboratory, with some duplicate
samples also tested by a specialist laboratory in a major research institute.
Measurable 14C well above background was obtained in all cases.

More recently, as a check on the AMS results in the
peer-reviewed literature, the RATE team acquired a suite of ten coal samples
from the U.S. Department of Energy Coal Repository. These samples represent
important U.S. coal deposits and span the geological record from Carboniferous
to Eocene. The 14C measurements by one of the best AMS laboratories
in the world for these ten samples are displayed in graphical form in Fig. 8 and discussed in Baumgardner et al.29 The 14C levels for
these samples fall nicely within the range of values shown in Fig. 7. We
conclude that the well-documented evidence of 14C in fossil organic
material provides compelling support for the young earth Creation-Flood model
and represents a severe challenge for the uniformitarian assumptions underlying
the long half-life radioisotope methods.

Tentative Conclusions

At this point in the RATE research several tentative
conclusions are beginning to emerge, based on the literature searches,
theoretical studies, and laboratory findings. Although some are firmer than
others, the following conclusions are likely to be in the final report. There
will likely also be additional conclusions which are too early to include at
this time. The tentative conclusions will only be reported here in outline
form. More detail and justifications for most of these conclusions are
discussed in the referenced papers in these Proceedings.

Conventional radioisotope dating methods
are unreliable.

Discordance among different dating
methods is common.

Key assumptions underlying radioisotope
dating methods are untenable.

Mixing of mantle and crustal
sources also mixes their isotopic signatures.

Residual 14C appears to be
present in all fossil biogenic material.

Massive nuclear decay has occurred in
rocks.

Large quantities of daughter elements
like Pb, He, and Ar are present.

Many of the daughter elements are in
proximity to the parent elements.

Fission tracks and radiohalos are
numerous.

Isotopic mixing between the earth’s
mantle and crust has occurred.

Lava flows exhibit isotopic
characteristics of the mantle.

Isotopic data suggest basalts were
generated from melting of old mantle.

Isotopic data also suggest basalt
magmas were contaminated during their ascent.

Residual He and radiohalos suggest recent
nuclear decay.

Large quantities of He are still present
in many granites today.

If He was formed millions of years ago,
it should have already escaped.

Experimentally-determined diffusion
rates of He agree with recent production of He.

Po halos appear to have formed during
rapid cooling of granite plutons during the Flood (eliminating millions of
years).

If the cooling of the plutons was rapid,
then metamorphism was also rapid during the Flood (eliminating millions of
years).

Summary

The basic conclusion of this research is that
conventional radioisotopic dating methods are unreliable. The chief reason is
that uniformitarianism is not a legitimate model of earth history.
Observational evidence supports the recent occurrence of a global catastrophic
Flood. Because the earth has suffered a major tectonic catastrophe
corresponding to the Genesis Flood, the uniformitarian assumptions that are
applied to obtain age estimates from radioisotopic data are simply not true.
Intermediate results from RATE support a young-earth, catastrophic, creationist
model.

Two remaining years in the research phase will be needed
to complete the analysis of samples yet being processed and theoretical studies
still being made. By the end of the research phase the final report should be
based on a larger data set than was available for this paper. A few research
projects within RATE such as Fission Tracks and Biblical Word Studies that
have not been discussed in this paper are also expected to contribute to the
final report. It is apparent that significant progress has been made in
explaining the presence of large quantities of nuclear decay products in a
young-earth time frame. The evidence should be stronger and more convincing by
the time the research project is completed in 2005. We also hope that by then a
more detailed young-earth creationist model of the history of radioactive decay
will also have been developed.

Acknowledgments

Appreciation is expressed to the many donors who
contributed financially to RATE. Los Alamos National Laboratory provided
samples of Jemez granodiorite for chemical and radioisotope analyses and Grand
Canyon National Park and Yosemite National Park granted permission to Drs.
Austin and Snelling to collect rock samples.

Snelling, A. A. 1998. The cause of anomalous
potassium-argon “ages” for recent andesite flows at Mt. Ngauruhoe, New Zealand
and the implications for potassium-argon “dating.” In, Walsh, R. E. (ed.), Proceedings of the fourth international conference on
creationism, pp. 503–525.

Snelling, A. A. 2000b. Geochemical processes in the
mantle and crust. In, Vardiman, L., A. A. Snelling, and E. F. Chaffin (eds.), Radioisotopes and the age of the earth: A young-earth
creationist research initiative, pp. 123–304. El Cajon, California: Institute for
Creation Research and St. Joseph, Missouri: Creation Research Society.

Snelling, A. A. 2003a. The relevance of Rb-Sr, Sm-Nd, and
Pb-Pb isotope systematics to elucidation of the genesis and history of recent
andesite flows at Mt. Ngauruhoe, New Zealand, and the implications for
radioisotope dating. In, Ivey, R. (ed.), Proceedings of the fifth international conference on
creationism, pp. 285–303. Pittsburgh, Pennsylvania: Creation Science
Fellowship.